They can find it out for themselves. To use my religion, you can take what's said in the Bible and compare it to how people act and interact. Also, the teaching process involves the converts asking questions so that still proves that religion does permit questioning. Also, offering proof or explanations involves religious apologists or theologians answering questions, once again demonstrating that religion (or at least some religions) allows questions.
Scientology certainly has taken hits when its beliefs have been examined. How many religious beliefs can you name that have been disproven and from more than one religion?
To take one example in the Bible, read what happens to Moses and the Burning Bush in Exodus 3 - whether you believe it really happened or not, the fact remains that Moses asks God numerous questions and does God say "no questions"? No, He gives Moses answers. Long story short, some religious people, just like non-religious people, don't like their beliefs getting questioned but religions - including Christianity because that's the religion I follow and your favorite one to target - do allow questions, end of story.